Unhappy plants !!

Not sure what's going on.
My larger plants are 12 days in from first set of real leaves.
They moved along good while in dixie cups. Good root growth. Transferred into 1 gallon about a week ago. Now in 1/3 FFOF and 2/3 pro mix hp. Under HO t5 with mixed 6500k and 3000k bulbs.
Water is between 6 and 7 ph.
Leaves are looking weird.
The plants have also been topped once.
Temps in the 70's
Humidity around 65%
Used one feeding of FF Grow big and big bloom @ 1/2 dose 5 days ago to see if it would correct a possible deficiency.
I may have topped to early,but seems to be growing fine under the cut.
What yall thinking?
Cheers

 

Light is 8" from tops. Any lower and canopy gets to 81-83.
I have a new full spectrum Led coming this weekend.
Run off ph was 6.2 last night with strips. Gonna recheck water and soil this weekend when I get my new meter.

 

Ok...
So water ph is ok
I tested my soil and found the ph to be somewhere between 6.5 and 7.
I than checked Nitrogen content.
It is a little hard to read but appears to be way low on N .
Maybe its time to get the nutrient feeding up to full strength. I really thought the FFOF was too hot for young plants. Next potting will be without the pro mix and using perlite to take it's place.
The other issues I believe to be a mix of heat stress,low RH and over watering . This is a rookie mistake and I should have known better. So I hope I have these issues resolved over the next week. I think the plants will bounce back. I will post up results. Here are the pics of my samples and the plants.